1. Field of the Invention
This invention relates to a magnet control device for use in a camera, and more particularly to an improvement in a magnet control device for controlling the start of an operation of a drive mechanism in a photographic camera.
2. Description of the Prior Art
In the photographic camera, it has been known to control a drive mechanism by use of a magnet. For instance, after driving energy has been charged in a drive mechanism, the operation of the drive mechanism is prevented until the operation should be started by use of a holding means utilizing a magnet. In a shutter drive mechanism, for example, an electromagnet is used for holding a driving member for a desired period with very fine accuracy of as short as 1/1000 second. The electric control is very advantageous in that the timing control can be conducted with very high accuracy.
Even when such an electromagnetic control means is used, however, the reliability of the drive mechanism is greatly influenced by the accuracy of the mechanical structure of the drive mechanism. The accuracy of the mechanical structure greatly depends upon the accurate face-to-face contact of the attracting face of the magnet and the attracted face of the attracted member pivotally mounte on a control lever associated with the control mechanism of the camera.
When the attracting face of the magnet and the attracted face of the member are not in perfect face contact with each other, the attracting force acting therebetween is markedly lowered and there is a possibility of malfunction of the mechanism. At worst, there is a possibility that the attracted member moves apart from the attracting face of the magnet before the magnet is demagnetized. Further, there are possibilities that the timing of separation of the attracted member from the attracting magnet is not accurately controlled.
The imperfect face-to-face contact between the magnet and the attracted member is caused generally by errors in mounting the various elements and members in the control mechanism. Particularly when those parts are assembled together, it is very difficult to assemble all those parts with perfect accuracy. There may be errors in the relative positions in the assembled mechanism, generally. Further, the adjustment of the various parts of the mechanism conducted after assembling is very delicate and necessitates a great skill.
Therefore, it is desired that those parts are automatically adjusted properly when those parts are assembled with insufficient adjustment.